SDM Lenses


Link Posted 26/02/2012 - 03:26
I think its a shame people are put of buying these fine lenses for fear of failure.

I have owned a 50-135mm for nearly four years now & its my favourite lens. It has yet to fail me apart from it snapping which is another story. If SDM does fail out of warranty then a repair cost around 100 will sort it, I hear with a new upgraded motor??

I think a lot of these surveys are so poorly monitored you are more likely to hear about the failure rate as people who lenses fail look for a solution on google then find the forums & then post and add to the polls skewing the figures even more...

Remember the number of Pentax users far far far outnumber the number of Pentax forum members...
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Currently on a Pentax hiatus until an FF Pentax is released

Dr. Mhuni

Link Posted 26/02/2012 - 09:55
I've had a DA17-70 for over three years and a DA*50-135 for almost one and have had no problems with either. In fact the 17-70 works better than ever on my K5.

I thought it was the older DA* lenses that had a serious problem with their SDM failing, not the 17-70? The latter can sometimes be hesitant - though as Mattmatic has noted, this is easily solved, and isn't really an issue on my K5.



Link Posted 26/02/2012 - 13:14
The problem with searching the web for reported problems is that generally only those with a problem mention that they have a problem. Very quickly rumours run wild with people conidering buying something prefacing their posts with "I'm looking at buying xxxxx from yyyyy but the web is full reports of problems..." which only adds to the Google search results. Also there's a lot of sites that scrape content off other sites with all appear as a 'problem-fest' in Google.

Very few satisfied owners will bother to post "My lens is great, always works, no problems."

Reviews are also two-appenny with millions of them available on the net and YouTube as more people want to have their say. Without knowing the skills of the reviewer it is very difficult to know how reliable they are.

It does however highlight the benefits you get buy buying gear from a dealer who can easily provide waranty support.
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Link Posted 26/02/2012 - 20:49
Have 16-50 and 50-135, no problems.


Link Posted 26/02/2012 - 23:04
I also have the 16-50 and 50-135 lenses, 2-3 years old and both are working fine.
K5 & K10D, various Pentax lenses


Link Posted 27/02/2012 - 00:06
I have the 16-50 (one of the first ones), 50-135 and 60-250 and all have been working fine.


Link Posted 27/02/2012 - 12:04
Nice to hear that plenty of users here have SDM lenses that work well and don't actually have issues! What happens if they do go wrong though? Does the focus jam, or anything else stop working, or can they still be used fully functionally minus having to focus manually?
Better equipment enhances my ability to display my shortcomings.


Link Posted 27/02/2012 - 21:39
From information posted elsewhere on the net, if SDM stops working the lens can continue to be used as a manual focus lens on any digital Pentax camera. If you have a K10D or earlier camera you may be able to make the lens work as a screw drive focus lens. To do this on a K10 you have to uninstall current firmware and re-install version 1.1 or earlier, I believe.

Earliest version of firmware left K10 working the SDM lenses as screwdrive instead of as SDM through the contacts. I believe other earlier Pentax digital cameras don't recognise SDM and operate these lenses as screwdrive. SDM and screwdrive systems are independant, so if SDM goes screwdrive is unaffected.

Cameras from K20 onwards recognise SDM lenses and won't operate them on screwdrive, even if SDM fails. Some who have failed SDM lenses have tried blocking off contacts etc to "trick" cameras into using screwdrive but I haven't read of any successes yet. There is pressure from some on Pentax also to give a software fix to allow users to select screwdrive in the event of SDM failure but you can see the difficulty that they would face - Pentax would be accepting that there were occasional (or indeed any) SDM failures.

Other advice I have read "out there" is to always store your SDM lenses on their sides, not on end, and to use them regularly. Those with failures commonly seem to have stored them on end and not to have used them for some time. Some suggest that failures seem to be associated with focus drive components becoming sticky or jammed due to combination of vertical method of storage and lack of use. I am sure there will also be plenty who store their SDM lenses like this and use them sparingly, but have had no problem!

Hard to know what to believe is best, it appears that the majority of users have no problem with SDM lenses, but there are clearly some out there who have had failures, albeit the failures seem more common in the earlier lenses. Nevertheless, I make sure my SDM lenses are stored on their sides and get a run on my camera every week, even if its only indoors, just as an insurance policy. Perhaps a sprig of lucky white heather in the kit bag helps too
K5 & K10D, various Pentax lenses
Last Edited by Ed110 on 27/02/2012 - 21:42


Link Posted 27/02/2012 - 22:22
insurance with protect your bubble works out at 7.79 per month..

Click here
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Concert photography

Currently on a Pentax hiatus until an FF Pentax is released


Link Posted 28/02/2012 - 01:26
@ Ed110 - very helpful and informative post, thanks for that!

I did not realise that the SDM lenses also have the screw system incorporated into the mount. It would seem logical on current and future cameras to incorporate selection of SDM or screw, and I think this would be a major selling point. Built in backup systems are never an admission of failure, they are a valuable asset (ask any pilot!) If current and future Pentax bodies DID allow the user to select screw or SDM it would immediately encourage more folks to buy the things by giving added peace of mind. At the end of the day if you have a screw drive system onboard both the lens and body anyway then it's crazy to disable the link!

Knowing the above, if I did spend a grand on an SDM lens and it ever failed I be even more annoyed!!! So the current situation is a double turn off!
Better equipment enhances my ability to display my shortcomings.


Link Posted 28/02/2012 - 07:54
I wouldn't worry too much, any teething problems will be way behind us by now. However, there are some lenses that are SDM only and they will only manually focus with pre-K10D with firmware 1.03 camera bodies. The 17-70mm is one. They are designated mount KAF3.
Best regards, John


Link Posted 28/02/2012 - 08:04
Absolute worst case scenario ..... get the SDM repaired, 100. Pentax. Pentax DA*300/4, Cosina 55/1.2, Lens Baby Composer Pro & Edge 80, AFA x1.7, Metz 50 af1.
Nikon. D800. D600. Sigma 500/4.5, Nikon 300/2.8 VRII, Sigma 120-300/2.8, Zeiss Distagon ZF2 21/2.8, Zeiss Distagon ZF2 35/2.0, Sigma 50/1.4, Nikkor 85/1.8, Nikon TC20EIII, Nikon TC14EII, Kenko x1.4, Sigma 2.0
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